With reference to FIG. 1, as is known in the art, the Public Switched Telephone Network (PSTN) 10 includes mechanisms for directing certain calls, such as an emergency 9-1-1 call, to a Public Safety Answering Point (PSAP) 20. For example, consider an end office (EO) 30 serving a wireline or landline end user device (EUD) 40 (e.g., a telephone) from which a 9-1-1 call is placed. The EO 30 commonly includes a telecommunications switch 32 (e.g., a class 5 switch such as the Lucent Technologies 5ESS or another like switch) that is operatively connected, e.g., via a twisted-pair line or cable, to the EUD 40. When the switch 32 recognizes a 9-1-1 call, the call is routed, e.g., over the PSTN 10, to the PSAP 20 serving the geographic region in which the EUD 40 is located.
Typically, upon receiving a 9-1-1 call, the PSAP 20 queries an Automatic Line Identification (ALI) database (DB) using the telephone or directory number of the calling EUD 40. The ALI DB provides the PSAP 20 with information associated with the calling EUD 40, e.g., the geographic and/or physical location of the EUD 40 (i.e., a street address or other positional identification). In this manner, a proper response to the 9-1-1 call can be quickly and readily dispatched to the proper location or otherwise coordinated.
While generally acceptable for the landline EUD 40, advances in the telecommunications field have given rise to many situations where the foregoing approach has certain limitations. For example, there are now a wide variety of different types of EUDs employed by various end users or subscribers to engage in communications. These different EUDs have different capabilities and different characteristics. For example, mobile telephones and other mobile EUDs are different from landline telephones and EUDs insomuch as their location is generally not fixed like the landline EUDs. Accordingly, the PSAP 20 may not be able to readily determine the location of a mobile EUD simply from its telephone number. Additionally, packet switched networks (such as the Internet or a managed private network) are being used to route voice telephone calls. Generally, this is known as voice-over-packet telephony, which includes, but is not limited to, VoIP (Voice over Internet Protocol). One of the advantages of voice-over-packet telephony is the ability for users to access the PSTN 10 through a telecommunications switch other than their current local switch. Various types of EUDs are available for end users to participate in voice-over-packet telephony, e.g., an IP telephone, which may be a hardphone or a softphone running on a laptop computer or other like platform. Furthermore, various EUDs may be equipped to communicate using a variety of different modes and/or telecommunication services. For example, common EUDs (e.g., landline telephones, desktop or laptop computers, personal digital assistants (PDAs), mobile telephones or mobile stations, etc.) may support any one or more of a voice-based service, text messaging, instant messaging, short message service (SMS), electronic mail (e-mail), etc.
In short, the various EUDs now in use have a range of differing portability and a range of different communication modes. For example, the EUD may have limited portability, such a desktop computer that may be moved from location to location and reconnected to a local area network (LAN), or it may have may limited mobility, such as a handheld terminal with in-building or on-campus access to a WiFi access point. Alternately, the EUD may have extensive mobility and be connected by wireless access to the public cellular or wireless network. The common element is that there is no fixed, permanent location associated with the EUDs as had been the case with traditional wireline or landline EUDs, and there are now a plurality of optional communication modes available to the EUDs. Nevertheless, it remains desirable to permit users of these various types of EUDs and various services to take advantage of the emergency calling network infrastructure already in place, i.e., the PSAPs and the 9-1-1 emergency calling feature.
Accordingly, a new and improved function supported on an end user telecommunications device for handling emergency calls is disclosed that overcomes the above-referenced problems and others.